The exhaust flap reduces the noise level when the engine is idle and when the engine speed is close to idle. This reduces the outlet noise to improve comfort for the customer.
The reduction in outlet noise is appr 8db .

The engine control activates the exhaust valve.
The degree of opening depends on gear, engine load and engine speed (see chart below).
Only two conditions , open and closed, occur while driving.

If the exhaust flap is faulty (or tempered with) the exhaust system will emit a hissing noise at high engine speeds when it's closed.
If the exhaust flap is defective and partially open a humming noise will be generated at idle.

Just making sure this is read correctly...To clarify (and correct me if I am wrong) the exhaust valves being wired open has no side effects other than louder note (slightly). That was my experience. There si no hissing or humming whatsoever. Now having modified OEM without valves and different piping it sounds fantastic.

Just making sure this is read correctly...To clarify (and correct me if I am wrong) the exhaust valves being wired open has no side effects other than louder note (slightly). That was my experience. There si no hissing or humming whatsoever. Now having modified OEM without valves and different piping it sounds fantastic.

Correct (on the side effects)
I think the hissing/humming is something some very sensitive drivers might hear. Probably not folks looking for a more pronounced exhaust note

The exhaust flap reduces the noise level when the engine is idle and when the engine speed is close to idle. This reduces the outlet noise to improve comfort for the customer.
The reduction in outlet noise is appr 8db .

The engine control activates the exhaust valve.
The degree of opening depends on gear, engine load and engine speed (see chart below).
Only two conditions , open and closed, occur while driving.

If the exhaust flap is faulty (or tempered with) the exhaust system will emit a hissing noise at high engine speeds when it's closed.
If the exhaust flap is defective and partially open a humming noise will be generated at idle.

I am running a modified OEM muffler setup on my car. You can actually get those from Performing imports. It removes the valves altogether and replaces the OEM 45mm pipe with a 65mm to make it basically a straight thru system. Sounds very nice as well. Nice throaty V8 sound without any raspiness or over the top noise. They are also now in the process of developing prototype tips to enhance the look over the small OEM ones.

Would love to give this ago, I am planning on changing the system but this would be a cheaper solution, wonder if anyone in the UK has done it......

Guys, I just completed the valve opening mod and it's a nice improvement in sound. It took me about 30 minutes all in and I can notice the difference, especially at lower RPMs. If I can swing another 8-10db via some other mod, the exhaust would be perfect! My butt dyno also noticed a slight increase in response at lower RPMs, but that could be in my head...or butt.

Guys, I just completed the valve opening mod and it's a nice improvement in sound. It took me about 30 minutes all in and I can notice the difference, especially at lower RPMs. If I can swing another 8-10db via some other mod, the exhaust would be perfect! My butt dyno also noticed a slight increase in response at lower RPMs, but that could be in my head...or butt.

Thanks for the detailed explanation!!

Just done the mod myself this morning and agree it does make a nice little improvement, I think the other mods too stock would result in a good sound.....

Guys, I just completed the valve opening mod and it's a nice improvement in sound. It took me about 30 minutes all in and I can notice the difference, especially at lower RPMs. If I can swing another 8-10db via some other mod, the exhaust would be perfect! My butt dyno also noticed a slight increase in response at lower RPMs, but that could be in my head...or butt.

Thanks for the detailed explanation!!

You should call Ron@Performing Imports and ask him about a modified OEM exhaust. If you like the sound you have just created you will get a bit throatier and louder without it being obnoxious.

Noelle does replace the internal piping with larger diameter pipes (from 59mm to 65mm) (see pic) and also removes the exhaust valve.

Thanks JMH,
Yes, it makes sense. They will be removing the very short baffled pipes inside the rear silencers, effectively, making the exhaust a straight through version, so more noise. I bet it sounds very good, and not a £million to do, regards, SIMON.

Thanks JMH,
Yes, it makes sense. They will be removing the very short baffled pipes inside the rear silencers, effectively, making the exhaust a straight through version, so more noise. I bet it sounds very good, and not a £million to do, regards, SIMON.

Btw you can also modify the vacuum setup so the exhaust valves are ALWAYS open , no need to use chicken/barb wire at all. Looks OEM and works perfectly. Over night the valves will close (loosing vacuum) but as soon as you start the engine they'll be open again.
I will take some detailed pictures/info when I get back from my trip next weekend.

Btw you can also modify the vacuum setup so the exhaust valves are ALWAYS open , no need to use chicken/barb wire at all. Looks OEM and works perfectly. Over night the valves will close (loosing vacuum) but as soon as you start the engine they'll be open again.
I will take some detailed pictures/info when I get back from my trip next weekend.

Btw you can also modify the vacuum setup so the exhaust valves are ALWAYS open , no need to use chicken/barb wire at all. Looks OEM and works perfectly. Over night the valves will close (loosing vacuum) but as soon as you start the engine they'll be open again.
I will take some detailed pictures/info when I get back from my trip next weekend.

The exhaust flap reduces the noise level when the engine is idle and when the engine speed is close to idle. This reduces the outlet noise to improve comfort for the customer.
The reduction in outlet noise is appr 8db .

The engine control activates the exhaust valve.
The degree of opening depends on gear, engine load and engine speed (see chart below).
Only two conditions , open and closed, occur while driving.

If the exhaust flap is faulty (or tempered with) the exhaust system will emit a hissing noise at high engine speeds when it's closed.
If the exhaust flap is defective and partially open a humming noise will be generated at idle.

Btw you can also modify the vacuum setup so the exhaust valves are ALWAYS open , no need to use chicken/barb wire at all. Looks OEM and works perfectly. Over night the valves will close (loosing vacuum) but as soon as you start the engine they'll be open again.
I will take some detailed pictures/info when I get back from my trip next weekend.

Hi jmh, any news on this as mine on order (LCI October delivery) and I want to do this.

Ive watched these valves, over the couple of months ive owned the car, and all i can see, is that the valves are closed, for a couple of minutes, during warm up, and then open from then onwards. So, all i can see these valves are used for, is for helping the cats, and the engine to warm up quicker ?. They are open all the time when the car is up to temp. So i dont really see the point of wiring them open, because they are always open anyway, when warm, regards, SIMON.

Ive watched these valves, over the couple of months ive owned the car, and all i can see, is that the valves are closed, for a couple of minutes, during warm up, and then open from then onwards. So, all i can see these valves are used for, is for helping the cats, and the engine to warm up quicker ?. They are open all the time when the car is up to temp. So i dont really see the point of wiring them open, because they are always open anyway, when warm, regards, SIMON.

OK Simon, thats good then, I think the quicker the warm-up on this engine the better.